When it comes to live troubleshooting or to ensure certain traffic is either blocked or allowed one relies heavily on logs, Palo Alto Network Firewalls does provides very good logging options and fields. Its quite easy to read them and understands them. By default when some one creates any security policy Palo Alto Networks Firewall logs the details at the end of the session. So one does not need to enable logging, if he/she wants to monitor session since it started then they have enable the it.
One can enable logging, directly from the security policy he/she creates as shown below